The present invention relates to codes and is concerned particularly with codes having two parts, which two parts are related.
Graphic, machine-readable codes are commonly used, for example, to identify articles such as consumer products. Several popular codes are currently used, including one and two-dimensional barcodes and matrix-style codes. In each case the code is applied to an article and enables the article to convey information about itself such as the identity of the manufacturer, and the article type.
One sophisticated type of machine readable code is described in our UK Patent No. GB 2383878 (the entire contents of which are incorporated herein by reference) and commercially available under the trade mark FractureCode®. Advantages of this type of code over other commercial machine-readable codes include a very high population of possible distinct codes as well as the ability to generate unique codes at very high speed.
Articles, such as consumer products or their packaging, are marked with such codes. In order to obtain information about the article, the code must be read by a machine which first performs a scanning operation to acquire digitally an image of the code. The image is then processed electronically to derive, via application of an algorithm, an alphanumeric character string that may be used to look up data corresponding to the article in a database.
Another major advantage of this code is the difficulty with which the code may be copied. The code, which typically comprises a rectangular box delimiting a series of intersecting lines, is difficult to copy to the degree of accuracy needed such that when read by a machine the same alphanumeric character string would be generated. This feature is partly a function of the level of detail, including thicknesses of lines and accuracy of angles therebetween, at which the scanning equipment acquires the image during reading. A further difficulty for would-be counterfeiters, is that many of the codes used are no more than 1 mm by 1 mm in area and may be printed in ultraviolet inks, infrared inks or other security inks.
A major security advantage of such codes is the fact that at the time of their creation they carry no information whatsoever, but must be scanned, converted into an alphanumeric character string using the algorithm and then related to data held in a database. Only then do they become meaningful.
Thus, without the algorithm, there is no way of deriving the information. A corresponding benefit is that even if a code can be reproduced accurately it cannot be applied to a different product from that to which it was originally applied without this fact becoming immediately detectable by a person undertaking a legitimate scanning/lookup operation.